Device for removing doses of plastic material from an extruder

ABSTRACT

A device for removing doses of plastic material from the outflow orifice of an extruder by means of at least one removal element movable with respect to the extruder and provided with a receptacle for a dose removed from the orifice, the removal element comprising a severing element adapted to cut into the plastic material dispensed by the extruder along a severing edge advancing through the material from one side of the orifice to the other, the receptacle being shaped so as to accomodate the dose and allow its expulsion substantially in the directon of the severing edge.

This application is the US national phase of international applicationPCT/EP2003/004214 filed 23 Apr. 2003 which designated the U.S. andclaims benefit of IT BO2002A000683, filed 31 Oct. 2002. The entirecontents of these applications are incorporated herein by reference.

1. Technical Field

The present invention relates to a device for removing doses of plasticmaterial from an extruder.

2. Background Art

Devices for removing doses of plastic material from an extruder anddepositing them in input to a carousel that is adapted for example toform by compression molding articles such as closures, caps, liners andthe like are currently known with particular reference to U.S. Pat. Nos.5,603,964, 5,807,592, and 5,811,044.

These devices are generally constituted by a rotating disk on whichconcave cup-like elements are distributed peripherally; said cups movealong a circular path that is substantially tangent to the orifice forthe outflow of the plastic material from the extruder; in their motion,the cups remove from said orifice, by scraping, preset quantities ofplastic material, subsequently unloading them with the aid of pneumaticor mechanical devices into respective cavities provided in the carousel,where they are then compressed in order to form the articles.

With such cups, the individual doses are formed by severing the flow ofplastic material that exits from the extruder. This severing methodcauses alterations to the physical characteristics of the material,which though being localized, are memorized in the material and cause inthe finished product defects that are sometimes not tolerable.

DISCLOSURE OF THE INVENTION

The aim of the present invention is to obviate the cited drawbacks byproviding a device that is adapted to remove from the extruder doses ofplastic material in the pasty state that maintain the intended physicaland mechanical characteristics, thus producing finished products thatare substantially free from defects.

Within this aim, an object of the present invention is to provide aremoval device that is improved so as to work at a higher speed thanconventional devices and is therefore capable of ensuring a higherproductivity.

Another object of the present invention is to provide a structure thatis simple and safe and effective in operation in order to be able towork with materials of different kinds.

This aim and these and other objects that will become better apparenthereinafter, are achieved by the present device for removing doses ofplastic material from an extruder by means of at least one removalelement that can move with respect to said extruder and is provided witha receptacle for a dose removed from the outflow orifice of saidextruder, wherein said removal element comprises a severing element thatis adapted to cut into the plastic material dispensed by said extruderalong a severing edge that advances through the material from one sideof said orifice to the other, and said receptacle is shaped so as toaccommodate said dose and allow its expulsion substantially in thedirection of said severing edge.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages will become better apparent from thedetailed description of some embodiments of the invention, illustratedonly by way of non-limitative example in the accompanying drawings, inwhich:

FIG. 1 is a partially sectional plan view of the device according to afirst embodiment;

FIG. 2 is a partially sectional side elevation view, taken along avertical plane, of the device of FIG. 1;

FIG. 3 is a partially sectional detail plan view of the device of FIG.1;

FIG. 4 is a partially sectional front elevation view of a firstconstructive embodiment of the device according to the invention;

FIG. 5 is a sectional view, taken along the line V-V of FIG. 4;

FIG. 6 is a partially sectional side elevation view of a secondconstructive embodiment of the device according to the invention;

FIG. 7 is a partially sectional front elevation view of the secondembodiment of FIG. 6;

FIG. 8 is a partially sectional plan view of a third embodiment;

FIG. 9 is a partially sectional plan view of a fourth embodiment;

FIG. 10 is a sectional plane view, taken along the line X-X of FIG. 9;

FIG. 11 is a partially sectional plan view of a fifth embodiment;

FIG. 12 is a partially sectional plan view of a sixth embodiment;

FIG. 13 is a partially sectional plan view of a seventh embodiment;

FIG. 14 is a partially sectional plan view of an eighth embodiment.

WAYS OF CARRYING OUT THE INVENTION

In the examples of the embodiments that follow, individualcharacteristics, given in relation to specific examples, may actually beinterchanged with other different characteristics that exist in otherexamples of embodiments.

With particular reference to FIGS. 1 to 3, the reference numeral 1generally designates a device according to the invention for removingdoses of plastic material to be fed into a molding carousel 2, asdescribed in the above cited U.S. patents, which is suitable to moldarticles such as closures or liners. For the sake of brevity in thedescription of said carousel, the footing 3 of said carousel is shownschematically; said footing supports, so that it can rotate about avertical axis A, a circular turntable 4 that is provided peripherallywith a plurality of recesses 5 that constitute the article moldingchamber and are part of the lower mold parts of compression-moldingunits. The turntable 4 turns in the direction B, so that the recesses 5trace a circular path, designated by C, and are fed with doses 6 ofplastic material.

The device 1 for removing the doses 6 comprises a disk 7, which canrotate about an axis D that is parallel to A. The disk 7 lies on a planearranged above the turntable 4, and multiple dose removal elements 8 arerigidly coupled to its lower face and arranged along a circumference Ethat is concentric to the axis D and tangent to the circular path C.

The removal elements 8 are angularly equidistant with respect to theaxis D and in step with the recesses 5, so that each element 8 issuperimposed on a respective recess 5 in the point of tangency F of thecircumference E with respect to the path C.

As shown more clearly in FIG. 3, each element 8 is constituted by anL-shaped member that is composed of a rectangular base 9 that rests onthe lower face of the disk 7 and in which there are two slots 10,through which screws 11 are guided which engage in the disk 7 in orderto fix the base under the disk 7.

A back wall 12 is rigidly coupled to the base 9 and is perpendicularthereto and substantially radial with respect to the axis D. A side wall13 and respectively a severing or cutting element 14, that could beconstituted by a blade, are fixed to the opposite ends of the wall 12,and form a receptacle 15 that is open, in the direction G of therotation of the disk 7, toward the region where the doses 6 of plasticmaterial are removed. The blade 14 has a cutting or severing edge 14 athat could be perpendicular to the disk 7 and is fixed so that it ispossible to adjust the distance of the cutting edge 14 a from the backwall 12.

It should be noted that the slots 10 are arc-shaped and their center islocated in the receptacle 15, so as to be able to adjust theirorientation with respect to the direction of rotation G of the disk 7.

The disk 7 is keyed on a vertical shaft 16 (see FIG. 2), which issupported, by way of bearings 17, in a sleeve 18 that is flanged onto anarm 19 that protrudes from the top of a column 20 on which it is mountedso that it can rotate about the axis H, which is parallel to D.

The rotating disk 7 is actuated by way of an adapted motor and atransmission device of the belt or gear type, which are not shown sincethey are fully conventional.

Proximate to the axis H, the arm 19 is provided with a lug 21, to whichthe stem of a fluid-operated actuator 22 is articulated; its cylinder isin turn pivoted in the footing 3 of the carousel. The fluid-operatedactuator 22 is designed to make the arm 19 perform an angular movementabout the axis H and therefore along the circumference E with respect tothe axis A of the carousel 2 until it more or less intersects the path Cof the recesses 5, so as to adjust, according to the requirements, theextent by which each removal element 8 remains superimposed on arespective recess 5 in order to allow the doses 6 taken by the elements8 to be deposited in the respective recesses.

The doses 6 to be deposited in the recesses 5 are dispensed by anextruder 23, which is provided with a nozzle 24 for the outflow of theplastic material that continues under the disk 7 and at the level of theremoval elements 8. The nozzle 24 is crossed by a channel 24a, whoseaxis L is perpendicular to the axis D, but is axially offset, withrespect to said axis D, laterally toward the point of tangency F. Thechannel 24 a is connected to the outside through a port that constitutesthe outflow orifice 24 b for the plastic material. However, it is notedthat in a fully similar manner the axis L can be arranged radially withrespect to the axis D, achieving the same functional result.

The orifice 24 b is formed by a rim 25 that is slightly concave, so asto lie on a substantially cylindrical surface, which in the specificcase is concentric with respect to the axis D. In this manner, theorifice has an elliptical shape whose central axis M passes through theaxis D.

The distance from the axis D of the rim 25 and of the cutting edge 14 aof the blade 14 are mutually identical, so that the blade 14 can grazethe rim 25 during the rotation of the disk 7.

Operation of the device is as follows: with the rotation of the disk 7,the blade 14 in fact severs a dose 6 from the stream 26 of plasticmaterial that exits from the orifice 24 b of the extruder 23 during thetime that elapses between the passage of two successive removal elements8 in front of said orifice. In particular, it should be noted that thecutting edge 14 a of the blade 14 allows to obtain a severing edge thatadvances through the stream 26 in the direction G and forms a dose 6whose physical characteristics are uniform throughout its thickness.

The blade 14 and the receptacle 15 could be orientated with respect tothe orifice 24 b so that the dose 6 can be easily accommodated in thereceptacle 15, where it is retained by the surfaces of the walls 12, 13and of the blade 14.

A fundamental prerogative of the device according to the inventionconsists of the fact that the arrangement of the blade 14 at rightangles to the disk 7 allows to provide a receptacle 15 which, inaddition to being open frontally, i.e. in the direction G toward theextruder 23, in order to receive the dose 6, is also open verticallydownward so as to allow to unload the dose into the respective recess 5of the carousel 2 by using an expulsion device that consist of a jet ofcompressed air, possibly assisted by the mechanical action of a piston,as described in the cited U.S. Pat. No. 5,807,598.

The invention is susceptible of numerous modifications and variations,all of which are within the scope of the same inventive concept.

FIGS. 4 and 5 illustrate a first constructive variation of the removaldevice, according to which the rotating disk 7 and the extruder 23 aremounted respectively so that the rotation axis D and the axis L of thenozzle 24 are horizontal and mutually parallel.

The removal elements 8 for the doses 6 are rigidly coupled to theperipheral region of the disk 7, and the cutting edges 14 a of theblades 14 are arranged radially and lie on a vertical plane that istangent to the rim 25 of the orifice 24 b for the outflow of the plasticmaterial. Below the disk there is the upper portion 27 of a conveyorbelt, on which closures 28 advance in succession, acting as areplacement of the recesses 5, the doses being successively punched intosaid closures in order to form the sealing liners.

The unloading of each dose 6 from the containment receptacle 15 into therespective closure 28 occurs parallel to the cutting edge 14 a of theremoval element 8, radially outward and in a diametrically oppositeposition with respect to the position for severing and removal from theoutflow orifice 24 b.

FIGS. 6 and 7 illustrate a second constructive variation of the feederdevice according to the invention, in which the extruder 23 is arrangedso that its axis L is vertical and the orifice 24 b is directeddownward. The rotation axis D of the rotating disk 7 is inclined withrespect to the vertical by 45° and has a substantially frustoconicalshape that tapers downward and forms an angle of 90° with the conicalsurface 29. In this manner, the removal elements 8 fixed onto theconical surface are orientated so that during the rotation of the disk 7the cutting edge 14 a is horizontal in the point of tangency with therim 25 of the orifice 24 b of the extruder 23 and is vertical in thediametrically opposite position in order to allow the unloading of thedoses into the closures 28.

FIG. 8 illustrates a third variation, in which the removal elements 8are provided with a device for retaining and releasing the doses 6. Forthis purpose, the side wall 13, which delimits the receptacle 15 on theopposite side with respect to the blade 14, is movable and is connectedto the back wall 12 by means of an elastic lamina 30, which allows itsarticulation with respect to the back wall 12 between a first endposition and a second end position. The position of the side wall 13 iscontrolled by a cam follower, which is constituted by an arm 31 that isrigidly coupled to the wall 13 and supports, at its end, a roller 32that engages on the profile of a stationary cam 33 that is concentric tothe axis D. The profile of the cam 33 is shaped so that when the blade14 has cut the dose 6, the side wall 13 is orientated toward the blade14 in the first end position, so as to grip and retain the dose.

FIGS. 9 and 10 illustrate a fourth variation, in which instead of theblade 14 there is a metallic wire 34 that is bent in a U-like shape withtwo portions 35 and 36 that are parallel and fixed to the back wall 12on the opposite side with respect to the side wall 13 and are joined bya portion 37 that is meant to cut the dose and is parallel to therotation axis C of the disk 7 for supporting the removal elements 8. Alip 38 protrudes from the wall 12, between the parallel portions 35 and36, and facilitates the accommodation of the severed dose in thereceptacle 15.

FIG. 11 illustrates a fifth variation, in which the portion of theoutflow channel 24 a that passes through the nozzle 24 has a curvedshape, such that its axis L coincides with the axis M of the orifice andis therefore radial with respect to the axis D of the disk 7: itsgeometry is therefore particularly suitable to achieve a correct,effective and uniform extrusion of the stream 26 of plastic material.

In a sixth constructive variation, shown in FIG. 12, each one of theremoval elements 8 has a side wall 13 that is articulated to the side ofthe base 9 about an axis N that is parallel to D. The side wall 13continues to the rear with a tab 39 that is shaped so as to interact, inthe motion of the disk 7 and according to a specific synchronization,with a cylindrical abutment 40, constituted for example by a roller thatis supported so that it can rotate about its own axis, which is parallelto D, and acts substantially as a stationary cam: this allows to achievethe rotation of the side wall 13 about the axis N, from a first endposition to a second end position and specifically in the direction ofthe opening of the receptacle 15, by the angle required to facilitatethe removal of the dose 6 on the part of the blade 14. A helicalcontrast spring 41, whose opposite ends respectively abut against thetab 39 and the base 9, prevents the rotation of the side wall 13 fromthe second end position to the first end position, i.e., in thedirection for closing the receptacle 15, so as to retain the dose 6after it has been removed. It should be noted that it may be possible,when the dose 6 is deposited in the respective recess 5, to provide anadditional roller, whose axis is parallel to D and which, by interactingwith the tab 39, reopens the receptacle 15, facilitating the release ofsaid dose into the receptacle.

A seventh constructive variation, shown in FIG. 13, differs from thesixth variation described above in that the tab 39 of the wall 13protrudes laterally, in a substantially radial direction with respect tothe axis D, and has an end portion that is in permanent contact with theend of the stem of a pneumatic piston 42 that is rigidly coupled underthe disk 7. The controlled extension of said stem, according to a presetsynchronization with respect to the motion of the disk 7, turns the sidewall 13 about the axis N from a first end position to a second endposition in the direction for opening the receptacle 15 by the anglerequired to allow the removal of the dose 6; the retention of said dosein the receptacle is then ensured by the actuation of the contrastspring 41, which returns the side wall 13 from the second end positionto the first end position.

When necessary, the further subsequent controlled extension of the stemof the pneumatic piston 42 causes the rotation of the side wall 13 againbetween the first end position and the second end position, releasingthe dose 6 into the respective recess 5.

FIG. 14 illustrates an eighth variation of the device according to theinvention, in which the end of the stem of the pneumatic piston 42 ofeach removal element 8, that could be of the double-acting type, isdirectly and rigidly connected to the side wall 13.

The controlled extension of the stem of the piston 42 when the dose 6 isremoved, allows to arrange the side wall 13 substantially adjacent tothe side of the base 9 in a first end position, thus closing thereceptacle 15 in order to firmly retain said dose. If required by thespecific application, the subsequent retraction, in step with therotation of the disk 7, of the stem of 30 the piston 42 allows to movethe side wall 13 away from the side of the base 9, i.e., in a second endposition, in order to produce the release of the dose 6 into therespective recess 5.

It has thus been shown that the invention achieves the intended aim andobjects.

All the details may further be replaced with other technicallyequivalent ones.

In practice, the materials used, as well as the shapes and thedimensions, may be any according to requirements without therebyabandoning the scope of protection of the appended claims.

The disclosures in Italian Patent Application No. BO2002A000683 fromwhich this application claims priority are incorporated herein byreference.

Where technical features mentioned in any claim are followed byreference signs, those reference signs have been included for the solepurpose of increasing the intelligibility of the claims and accordinglysuch reference signs do not have any limiting effect on the scope ofeach element identified by way of example by such reference signs.

1. A device for removing doses of plastic material from an extruder anddelivering the doses to a forming apparatus in which the doses arecompression-moulded, the device comprising at least one removal elementwhich is movable with respect to said extruder for removing a dose andis provided with a receptacle for receiving the dose removed from anoutflow orifice of said extruder, said removal element comprising asevering element that is adapted to cut into the plastic materialdispensed by said extruder along a severing edge that advances throughthe material from one side of said orifice to the other, said receptaclebeing shaped so as to accommodate said dose and allow expulsion thereofsubstantially in the direction of said severing edge, the receptacleretaining the dose while the at least one removing element moves from afirst position, in which the at least one removing element interactswith the extruder, to a second position, in which the at least oneremoving element interacts with the forming apparatus, the receptacledepositing the dose into a recess associated to said forming apparatusand defining a molding chamber for the dose, wherein said severing edgedefines a leading portion of said receptacle which is more advanced thana trailing portion of said receptacle in an intended direction ofmovement of said severing element.
 2. The device according to claim 1,wherein said removal element is provided with an inlet passageway, whichis partially bound by said severing edge and through which said dose isreceivable into said receptacle, and an outlet passageway, transverselyoriented with respect to said severing edge and through which said dosemay be expelled from said receptacle.
 3. The device according claim 1,wherein said severing element is so shaped as to interact with said doseto an extent not significantly greater than said severing edge.
 4. Thedevice according to claim 1, wherein said severing element isconstituted by a blade in which said severing edge is substantiallyperpendicular to the direction of advancement of said blade with respectto said extruder and is suitable to cut the plastic material along asurface that is tangent to the rim of the orifice of said extruder. 5.The device according to claim 1, wherein said severing element comprisesa metallic wire that is substantially perpendicular to the advancementdirection of said severing element with respect to said extruder and isadapted to cut the plastic material along a surface that is tangent tothe rim of the orifice of said extruder.
 6. The device according toclaim 1, wherein said removal element is supported in a manner thatallows adjustment with respect to said extruder in order to allow tokeep said severing edge on the plane of tangency with the rim of theorifice of the extruder.
 7. The device according to claim 1, whereinsaid removal element comprises an expelling device for expelling saiddose from said receptacle.
 8. The device according to claim 1, whereinsaid removal element comprises a back wall, the severing element that isfixed to a side of said back wall, and a movable side wall on theopposite side with respect to said severing element, said severingelement, said back wall and said movable side wall forming saidreceptacle, said side wall being controlled by an actuation device foractuation of said side wall between a first end position and a secondend position.
 9. The device according to claim 8, wherein said movableside wall is articulated to said back wall and has a rear tab that iscontoured so as to interact with a respective cylindrical abutment, andto actuate said side wall between said first end position and saidsecond end position, a contrast spring being provided which isassociated with said side wall in order to actuate said wall betweensaid second end position and said first end position.
 10. The deviceaccording to claim 8, wherein said movable side wall is associated withan end of a stem of a pneumatic piston for actuating said side wallbetween said first end position and said second end position.
 11. Thedevice according to claim 10, wherein said movable side wall is coupledrigidly to said end of the stem of said pneumatic piston.
 12. The deviceaccording to claim 8, wherein said movable side wall is connected tosaid back wall by means of an elastic lamina that is actuated by a camfollower.
 13. The device according to claim 12, wherein said camfollower is constituted by a roller that is supported by an arm that isrigidly coupled to said movable side wall of said removal element and iscontrolled by a stationary cam.
 14. The device according to claim 8,wherein in said first end position said movable side wall is arranged soas to retain, in said receptacle, said dose removed by said severingelement, and in that in said second end position said movable side wallis arranged so as to release said dose from said receptacle.
 15. Thedevice according to claim 8, for feeding doses of plastic material to amolding carousel, which comprises a disk that rotates synchronously withsaid carousel and peripherally supports said at least one element forremoving said doses, wherein the orifice for the exit of said doses hasa rim that lies on a surface that is substantially tangent to the planeof rotation of said severing edge.
 16. The device according to claim 15,wherein said disk is arranged with a rotation axis thereof vertical,said orifice is orientated substantially radially with respect to saidrotation axis, said removal element is rigidly coupled to the lower faceof said disk so that said severing edge is parallel to said rotationaxis, and said receptacle is open downward in order to allow to unloadthe dose in a direction that is parallel to said rotation axis into arespective recess of the carousel that lies below said removal element.17. The device according to claim 15, wherein said disk is arranged witha rotation axis thereof horizontal, said orifice is parallel to saidrotation axis, and said removal element is rigidly coupled to thelateral surface of said disk so that said severing edge is substantiallyradial with respect to the rotation axis of said disk, said receptacleof said dose being shaped so as to unload said dose in a direction thatis parallel to said severing edge.
 18. The device according to claim 15,wherein said disk is arranged with a rotation axis thereof inclined,said extruder is arranged so that its axis forms an acute angle withsaid rotation axis, and said removal element is arranged on said disk sothat said severing edge is tangent to said orifice.
 19. The deviceaccording to claim 15, wherein said disk is arranged with a rotationaxis thereof inclined and forms a lower face, said removal element beingrigidly coupled to said lower face so as to be orientated so that saidsevering edge is horizontal in an upper position for removing said doseand is vertical in a lower position for unloading said dose into arespective underlying recess.
 20. The device according to claim 15, andfurther comprising a plurality of said removal elements, which aredistributed peripherally with respect to the rotation axis of said diskand are angularly mutually equidistant.
 21. The device according toclaim 1, for feeding doses of plastic material to a molding carousel,which comprises a disk that rotates synchronously with said carousel andperipherally supports said at least one element for removing said doses,wherein the orifice for the exit of said doses has a rim that lies on asurface that is substantially tangent to the plane of rotation of saidsevering edge.
 22. The device according to claim 21, wherein said diskis arranged with a rotation axis thereof vertical, said orifice isorientated substantially radially with respect to said rotation axis,said removal element is rigidly coupled to the lower face of said diskso that said severing edge is parallel to said rotation axis, and saidreceptacle is open downward in order to allow to unload the dose in adirection that is parallel to said rotation axis into a respectiverecess of the carousel that lies below said removal element.
 23. Thedevice according to claim 21, wherein said disk is arranged with arotation axis thereof horizontal, said orifice is parallel to saidrotation axis, and said removal element is rigidly coupled to thelateral surface of said disk so that said severing edge is substantiallyradial with respect to the rotation axis of said disk, said receptacleof said dose being shaped so as to unload said dose in a direction thatis parallel to said severing edge.
 24. The device according to claim 21,wherein said disk is arranged with a rotation axis thereof inclined,said extruder is arranged so that its axis forms an acute angle withsaid rotation axis, and said removal element is arranged on said disk sothat said severing edge is tangent to said orifice.
 25. The deviceaccording to claim 21, wherein said disk is arranged with a rotationaxis thereof inclined and forms a lower face, said removal element beingrigidly coupled to said lower face so as to be orientated so that saidsevering edge is horizontal in an upper position for removing said doseand is vertical in a lower position for unloading said dose into arespective underlying recess.
 26. The device according to claim 21, andfurther comprising a plurality of said removal elements, which aredistributed peripherally with respect to the rotation axis of said diskand are angularly mutually equidistant.
 27. The device according toclaim 1, wherein said forming apparatus comprises a rotatable turntableprovided with lower mold parts of compression molding units in whichsaid molding chamber is defined.
 28. The device according to claim 1,wherein said forming apparatus comprises a conveyor belt on whichclosures advance, said molding chamber being defined in said closures.29. A device for removing doses of plastic material from an extruder anddelivering the doses to a forming apparatus in which the doses arecompression-moulded, the device comprising at least one removal elementwhich is movable with respect to said extruder for removing a dose andis provided with a receptacle for receiving the dose removed from anoutflow orifice of said extruder, said removal element comprising asevering element that is adapted to cut into the plastic materialdispensed by said extruder along a severing edge that advances throughthe material from one side of said orifice to the other, said removalelement being provided with an inlet passageway which is partially boundby said severing edge and through which said dose is receivable intosaid receptacle, wherein said removal element is further provided withan outlet passageway transversely oriented with respect to said severingedge and through which said dose may be expelled from said receptacle,the receptacle retaining the dose while the at least one removingelement moves from a first position, in which the at least one removingelement interacts with the extruder, to a second position, in which theat least one removing element interacts with the forming apparatus, thereceptacle depositing the dose into a recess associated to said formingapparatus and defining a molding chamber for the dose.
 30. The deviceaccording to claim 29, wherein said forming apparatus comprises arotatable turntable provided with lower mold parts of compressionmolding units in which said molding chamber is defined.
 31. The deviceaccording to claim 29, wherein said forming apparatus comprises aconveyor belt on which closures advance, said molding chamber beingdefined in said closures.